Optimizing the ship constructions by automatic line heating forming process based in numerical simulation and artificial intelligence

This paper presents the development of a novel automatic lineheating forming machine based on intensive application of the numerical simulation and artificial intelligence. The forming of certain parts of the shell of the ships can be done by heating forming or mechanical forming. Line heating forming is usually a more flexible process, and therefore, it is more useful. The principal problem with line heating forming is that it is very time consuming, manual and needs very qualified workers. In this research, line heating forming is studied looking for the best way to automate the process. Numerical models were developed based on finite element methods to simulate the process of heating, cooling and finally forming of the plates. The models were tested and validated against experimental test over small plates. However, as numerical models have extremely long computational times demanding high computational capacities; they are not directly applicable in a real time scenario, as it is needed. Finally, after the mathematization of this knowledge and making use of it, it was developed a software based on artificial intelligence. Using an informed heuristic search strategy, this software predicts the optimal set of heating lines, their sequence and velocity to be applied over the plate to obtain the final shape. The developed system was tested to show its feasibility. As a consequence, there is a significative reduction in computational time allowing the system to be applied in a soft real-time environment. This model will help shipyard manufacturers determine the positions and trajectory of torch for the flame heating lines and their heating parameters to form a desired shape of plate

PARALLEL SOLUTION OF THERMOMECHANICAL INVERSE PROBLEMS FOR LASER DIELESS DRAWING OF ULTRA-THIN WIRE

The paper discusses the solving of inverse thermomechanical problems requiring a large number of FEM tasks with various boundary conditions. The study examined the case when all tasks have the same number of nodes, finite elements, and nodal connections. In this study, the speedup of the solution of the inverse problem is achieved in two ways: 1. The solution of all FEM tasks in parallel mode. 2. The use by all FEM tasks a common matrix with addresses of nonzero elements in the stiffness matrices. These algorithms are implemented in the own FEM code, designed to solve inverse problems of the hot metal forming. The calculations showed that developed code in parallel mode is effective for the number of tasks late than 0,7-0,9 of the number of available processors. Thus, at some point, it becomes effective to use a sequential solution to all tasks and to use a common matrix of addresses of nonzero elements in the stiffness matrix. The achieved acceleration at the optimal choice of the algorithm is 2–10 times compared with the classical multivariate calculations in the FEM. The paper provides an example of the practical application of the developed code for calculating the allowable processing maps for laser dieless drawing of ultra-thin wire from copper alloy by solving the thermomechanical inverse problem. The achieved acceleration made it possible to use the developed parallel code in the control software of the laboratory setup for laser dieless drawing

FEM analysis of RF breast ablation: Multiprobe versus cool-tip electrode

Background: Radio-frequency ablation (RFA) has recently received much attention as an effective minimally invasive strategy for the local treatment of tumors. The purpose of this study was to evaluate the efficacy of single-needle cool-tip RF breast ablation in terms of temperature distribution and duration of the procedure as compared to multiprobe RF breast ablation. Materials and Methods: Two different commercially available radiofrequency ablation needle electrodes were compared. Finite-element method (FEM) models were developed to simulate the thermoablation procedures. A series of ex vivo radiofrequency thermal lesions were induced to check the response of the FEM calculations. Results: Data obtained from FEM models and from ex vivo procedures showed that cool-tip RF breast ablation assures better performances than multiprobe RF breast ablation in terms of temperature distribution and duration of the procedure. Histopathological analysis of the cool-tip RF thermoablated specimens showed successful induction of coagulation necrosis in the thermoablated specimens. Conclusion: Data obtained from FEM models and from ex vivo procedures suggest that the proposed cool-tip RF breast ablation may kill more tumor cells in vivo with a single application than the multiprobe RF breast ablation